Here’s another thought for you on ‘feeling like the aerodynamics are minutely different’.
Much of the study of aerodynamics has to do with what are referred to as ‘boundary layers’. I won’t get into that... you can do a search to figure out what that’s all about but you probably all ready can figure out what I’m talking abot. Anyway, the difference may have less to do with the change in temperature between 45 and 80 degrees than whether the sun is shining or not. Let me explain... When the sun is shining, the black pavement absorbs more heat and a boundary layer of hot air develops close to the pavement. This essentially creates a layer of air that is more buoyant and that may relate also to what you are feeling.
Not related to the aerodynamics is the fact that at higher temperature, the rubber on your tyres is softer and that of course makes the bike feel different as far as handling.
Not related to the aerodynamics is the fact that at higher temperature, the rubber on your tyres is softer and that of course makes the bike feel different as far as handling.
Tire temperature does indeed have an effect you can feel in handling. But interestingly enough it is not riding down the road that warms up the tires, it is braking and acceleration.
Thank you for confirming my belief that air density does affect the feel of the wind. Yeah, there is a whole basket of variables in the aerodynamics of riding a bike. Getting a windshield or windscreen (I use the latter) that works is so tough for every rider. I've got an essentially new windshield that I couldn't use regardless of how I adjusted it. Past 60 mph it destabilized the front end. I got a much smaller British made windscreen that for me is so much more effective in directing the airflow around my torso without that feeling of uh oh.